Five bright blue lights in formation streak across sky without making a sound

I was taking my one year old daughter down to the end of our driveway to pick up our empty trash can, when I noticed a seeming change in the darkness around us, as though something was lighting up the night. There are two houses being built beside us, so I thought that maybe a car or someone at one of the houses had turned on very bright lights.

As I was quickly processing this info, I happened to look up and saw five very bright blue lights absolutely zoom across the night sky, in single file formation, without making a sound. When I noticed the lights, they were almost directly overhead, perhaps a few thousand feet in the air, and they disappeared after only a few seconds, as they vanished into the distance.

I could not tell whether they simply flew out of view, or actually turned off, but they had obviously been visible before I noticed them overhead, as their light was so bright that, in the few seconds before I looked up, I had felt their light all the way down to ground level.

At the same time, a neighbor across the street was out on her porch, calling her dogs in, and after they disappeared from view, I asked her if she had seen the same thing I had just witnessed. She said that she had. I asked her what she thought it was, and she had no idea.

About 1 minute after the lights disappeared, a very distant boom could be heard, almost like a sonic boom from miles and miles away, but without any visible signs. About 5 minutes later, another boom was heard, again without any visual cues to what was going on, and then nothing more happened the rest of the night.